As described for example in U.S. Pat. No. 4,782,381, over the years integrated circuit (IC) structures have taken on several different configurations and have increased in complexity and capacity. Very large scale integration (VLSI) has now become very popular, where each such package includes hundreds of input and output terminals as well as operating potential terminals. Usually these terminals take the form of conductive pads or bumps. As every application usually requires different electrical functions to be performed, there are literally thousands of VLSI packages that have different assignments for similar terminal pad positions.
Although the electronics industry has tried to standardize micro electronic circuits in the form of integrated circuit chips, there are many more circuit designs that do not follow standards with respect to internal designs and external lead or pad placement or position.
Often, these special or proprietary chips have high pin counts and are arranged in non-standard, non-symmetrical pad patterns. Also, these devices usually have very high power dissipations and require very low power lead voltage drops for proper operation. Accordingly, most manufacturers are forced to design and build custom chip carriers for each I.C. design.
There are certain problems related to the use of custom chip carriers beyond the obvious one of the cost of designing a new chip carrier for each new I.C. Such a problem is in the area of scheduling. That is, most manufacturers experience difficulty in being able to provide a custom chip carrier in time to immediately accommodate a newly designed special I.C. chip. This is because the pad pattern for the I.C. is often not firmly established until just prior to releasing the design for part fabrication. The I.C. manufacturing process often takes as much as eight weeks, which is not sufficient time to design and fabricate a suitable custom chip carrier.
Therefore, it should be evident that there is a need for an easily fabricated selectable chip carrier that can be customized to match the requirements of a particular integrated circuit, and that the providing of such a device would constitute a significant advancement in the art.